duplex.js

"use strict";
/**
 * Duplex channel implementation for bidirectional streaming.
 *
 * Creates a pair of connected channels where data written to one
 * channel's writer appears in the other channel's readable.
 */
var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
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Object.defineProperty(exports, "__esModule", { value: true });
exports.duplex = duplex;
var push_js_1 = require("./push.js");
/**
 * Create a pair of connected duplex channels for bidirectional communication.
 *
 * Similar to Unix socketpair() - creates two endpoints where data written
 * to one endpoint's writer appears in the other endpoint's readable.
 *
 * @param options - Optional configuration for both channels
 * @returns A tuple of two connected DuplexChannel instances
 *
 * @example
 * ```typescript
 * const [client, server] = Stream.duplex();
 *
 * // Server echoes back what it receives
 * (async () => {
 *   await using srv = server;
 *   for await (const chunks of srv.readable) {
 *     await srv.writer.writev(chunks);
 *   }
 * })();
 *
 * // Client sends and receives
 * {
 *   await using conn = client;
 *   await conn.writer.write('Hello');
 *   for await (const chunks of conn.readable) {
 *     console.log(new TextDecoder().decode(chunks[0])); // "Hello"
 *     break;
 *   }
 * }
 * ```
 */
function duplex(options) {
    var _a, _b;
    var _c, _d, _e, _f;
    var _g = options !== null && options !== void 0 ? options : {}, highWaterMark = _g.highWaterMark, backpressure = _g.backpressure, signal = _g.signal, a = _g.a, b = _g.b;
    // Channel A writes to B's readable (A→B direction)
    var _h = (0, push_js_1.push)({
        highWaterMark: (_c = a === null || a === void 0 ? void 0 : a.highWaterMark) !== null && _c !== void 0 ? _c : highWaterMark,
        backpressure: (_d = a === null || a === void 0 ? void 0 : a.backpressure) !== null && _d !== void 0 ? _d : backpressure,
        signal: signal,
    }), aWriter = _h.writer, bReadable = _h.readable;
    // Channel B writes to A's readable (B→A direction)
    var _j = (0, push_js_1.push)({
        highWaterMark: (_e = b === null || b === void 0 ? void 0 : b.highWaterMark) !== null && _e !== void 0 ? _e : highWaterMark,
        backpressure: (_f = b === null || b === void 0 ? void 0 : b.backpressure) !== null && _f !== void 0 ? _f : backpressure,
        signal: signal,
    }), bWriter = _j.writer, aReadable = _j.readable;
    // Track closed state for idempotency
    var aWriterRef = aWriter;
    var bWriterRef = bWriter;
    var channelA = (_a = {
            get writer() {
                return aWriter;
            },
            readable: aReadable,
            close: function () {
                return __awaiter(this, void 0, void 0, function () {
                    var writer;
                    return __generator(this, function (_a) {
                        switch (_a.label) {
                            case 0:
                                if (aWriterRef === null)
                                    return [2 /*return*/];
                                writer = aWriterRef;
                                aWriterRef = null;
                                if (!(writer.endSync() < 0)) return [3 /*break*/, 2];
                                return [4 /*yield*/, writer.end()];
                            case 1:
                                _a.sent();
                                _a.label = 2;
                            case 2: return [2 /*return*/];
                        }
                    });
                });
            }
        },
        _a[Symbol.asyncDispose] = function () {
            return this.close();
        },
        _a);
    var channelB = (_b = {
            get writer() {
                return bWriter;
            },
            readable: bReadable,
            close: function () {
                return __awaiter(this, void 0, void 0, function () {
                    var writer;
                    return __generator(this, function (_a) {
                        switch (_a.label) {
                            case 0:
                                if (bWriterRef === null)
                                    return [2 /*return*/];
                                writer = bWriterRef;
                                bWriterRef = null;
                                if (!(writer.endSync() < 0)) return [3 /*break*/, 2];
                                return [4 /*yield*/, writer.end()];
                            case 1:
                                _a.sent();
                                _a.label = 2;
                            case 2: return [2 /*return*/];
                        }
                    });
                });
            }
        },
        _b[Symbol.asyncDispose] = function () {
            return this.close();
        },
        _b);
    return [channelA, channelB];
}